The present invention relates generally to access needles suitable for use in percutaneous endoscopic gastrostomy (PEG) procedures and percutaneous endoscopic jejunostomy (PEJ) procedures and relates more particularly to a novel access needle particularly well-suited for use in PEJ procedures.
Certain patients are unable to take food and/or medications transorally due to an inability to swallow. Such an inability to swallow may be due to a variety of reasons, such as esophageal cancer, neurological impairment and the like. Although the intravenous administration of food and/or medications to such patients may be a viable short-term approach, it is not well-suited for the long term. Accordingly, the most common approach to the long-term feeding of such patients involves gastrostomy, i.e., the creation of a feeding tract or stoma between the stomach and the upper abdominal wall. Feeding is then typically performed by administering food through a catheter or feeding tube that has been inserted into the feeding tract, with the distal end of the feeding tube extending into the stomach and being retained therein by an internal anchor or bolster and the proximal end of the feeding tube extending through the abdominal wall.
Although gastrostomies were first performed surgically, most gastrostomies are now performed using percutaneous endoscopy and result in the implantation of a gastrostomy feeding tube assembly (also referred to as a percutaneous endoscopic gastrostomy (PEG) device) in the patient. Two of the more common techniques for implanting a PEG device in a patient are “the push method” (also known as “the Sacks-Vine method”) and “the pull method” (also known as “the Gauderer-Ponsky method”). Information regarding the foregoing two methods may be found in the following patents, all of which are incorporated herein by reference: U.S. Pat. No. 5,391,159, inventors Hirsch et al., which issued Feb. 21, 1995; U.S. Pat. No. 5,167,627, inventors Clegg et al., which issued Dec. 1, 1992; U.S. Pat. No. 5,112,310, inventor Grobe, which issued May 12, 1992; U.S. Pat. No. 4,900,306, inventors Quinn et al., which issued Feb. 13, 1990; and U.S. Pat. No. 4,861,334, inventor Nawaz, which issued Aug. 29, 1989.
According to “the push method,” the distal end of an endoscope is inserted into a patient's mouth and is passed through the esophagus into the stomach. After distension of the stomach by inflation with air, an entry site on the abdomen is identified using the endoscope for transillumination, and an incision is made by passing the sharpened tip of a needle surrounded by a cannula (the combination of the needle and the cannula also referred to in the art as an “access needle”) through the abdominal wall and into the stomach. A snare is inserted into the stomach via the endoscope and is looped over the inserted end of the needle portion of the access needle. The snare is then “walked” up the needle until the cannula portion of the access needle is snared. The snared cannula is then pulled externally to tack the cannula to the stomach and, in turn, to secure the stomach wall to the abdominal wall. The needle portion of the access needle is then removed from the patient while keeping the cannula portion of the access needle in place. A first end of a flexible guidewire (also known in the art as a “pushwire”) is then passed through the cannula and into the stomach where it is grasped by the snare, the second end of the guidewire remaining external to the patient. The endoscope and the snare are then withdrawn from the mouth of the patient to deliver the first end of the guidewire.
A push-type catheter implanting assembly is then inserted over the first end of the guidewire and is pushed over the guidewire towards its second end. The push-type catheter implanting assembly typically comprises a gastrostomy feeding tube, the gastrostomy feeding tube having a dome-shaped internal bolster disposed at its trailing end and having a tubular dilator serially connected to its leading end. The gastrostomy feeding tube and the internal bolster are typically made of a soft, biocompatible material, like silicone rubber, and typically form a unitary structure. The dilator, which tapers in outer diameter from its trailing end to its leading end, is typically made of polyethylene or a like material which is stiffer than silicone but which still possesses some flexibility. Advancement of the push-type catheter implanting assembly over the guidewire continues until the front end of the dilator reaches the cannula and pushes the cannula out through the abdominal wall of the patient. The front end of the dilator is then pulled through the abdominal wall until the front end of the gastrostomy feeding tube emerges from the abdomen and, thereafter, the internal bolster at the rear end of the gastrostomy feeding tube engages the stomach wall. The guidewire is then removed from the patient. The clinician then re-intubates the patient with the endoscope and uses an optical channel in the endoscope to inspect whether the internal bolster is properly seated in the stomach.
If the internal bolster is properly placed against the stomach wall, a length of the externally-extending portion of the implanted gastrostomy feeding tube is then typically cut and removed from the implanted tube to reduce the externally-extending portion of the tube to a desired length (typically about 4-6 inches). (The removal of the leading end of the gastrostomy feeding tube also results in the removal of the dilator, which is connected thereto.) An external bolster is typically secured to the remaining externally-extending portion of the feeding tube to engage the abdomen in such a way as to prevent longitudinal movement of the feeding tube into the stomach. Additionally, a “Y-port” adapter is typically attached to the external end of the feeding tube, the Y-port adapter being adapted to receive a pair of connector tips through which food and/or medications may be dispensed. In addition, a detachable locking clip is typically secured to the implanted feeding tube at a point between the external bolster and the Y-port adapter to prevent gastric fluids from escaping through the proximal end of the feeding tube when the feeding tube is not in use.
The “pull method” is similar in some respects to the above-described “push method,” the pull method differing from the push method in that, after the cannula is snared and the needle is removed from its cannula, a looped first end of a suture (also known in the art as a “pullwire”) is inserted through the cannula and into the stomach where it is grasped by the snare, the second end of the suture remaining external to the patient. The endoscope and the snare are then withdrawn from the mouth of the patient to deliver the first end of the suture. The first end of the suture is then coupled to the leading end of a pull-type catheter implanting assembly, the pull-type catheter implanting assembly typically comprising a gastrostomy feeding tube having an internal bolster integrally formed at its trailing end and a plastic fitting attached to its leading end. The plastic fitting typically has a barbed rear portion mounted within the leading end of the feeding tube and a conical front portion that serves as a dilator, said conical front portion tapering in diameter from the leading end of the feeding tube to a front tip. A wire loop is fixed to the front tip of the plastic fitting, the first end of the suture being tied to the wire loop. Using the second end of the suture, the pull-type catheter implanting assembly is then pulled retrograde through the patient until the gastrostomy feeding tube emerges from the abdomen of the patient and the internal bolster engages the stomach wall of the patient. Next, as is the case in the push method, the clinician then re-intubates the patient with the endoscope in order to visually inspect the placement of the internal bolster within the stomach. If the bolster is properly seated in the stomach, the externally-extending portion of the implanted gastrostomy feeding tube is then typically cut to a desired length and one or more of an external bolster, a Y-port and a clamp are attached to the feeding tube.
Access needles of the type that are typically used in percutaneous endoscopic gastrostomies have their genesis in radiology and cardiology and typically come in two different varieties. One such access needle is referred to in the art as a Seldinger needle and comprises a solid metal needle (or stylet) removably mounted within a metal cannula. A plastic needle hub is fixed to the proximal end of the metal needle, and a plastic cannula hub is fixed to the proximal end of the metal cannula. The needle hub and the cannula hub are sized and shaped to permit a portion of the needle hub to be removably inserted into the cannula hub in such a way as to delimit insertion of the needle through the cannula. A tab is provided on the needle hub and a corresponding slot is provided on the cannula hub, said slot being adapted to receive said tab in order to permit said needle and said cannula to be placed in a particular rotational orientation relative to one another. The cannula hub is also shaped to include a lateral flange upon which a user may rest, for example, his forefinger and middle finger.
The other type of access needle commonly used to perform percutaneous endoscopic gastrostomies is an ANGIOCATH® access needle, which comprises a hollow metal needle removably mounted within a plastic cannula. A plastic needle hub is fixed to the proximal end of the metal needle, and a plastic cannula hub is fixed to the proximal end of the plastic cannula. The needle hub and the cannula hub are sized and shaped to permit a portion of the needle hub to be removably inserted into the cannula hub in such a way as to delimit insertion of the needle through the cannula. No means is provided in an ANGIOCATH® access needle for fixing the rotational orientation of the needle relative to the cannula when the needle hub is inserted into the cannula hub.
In both a Seldinger needle and an ANGIOCATH® needle, the lengths of the needle and the cannula are such that, with the needle fully inserted into the cannula, only the needle tip extends distally beyond the distal end of the cannula. Seldinger needles typically have a smaller diameter than do ANGIOCATH® needles (20 gauge needle and 18 gauge cannula vs. 16 gauge needle and 14 gauge cannula, respectively); however, more doctors have been trained using ANGIOCATH® needles and, therefore, are more comfortable with and use ANGIOCATH® needles.
Although gastrostomies are the most common approach to the long-term feeding of patients unable to swallow, there are situations in which it is desirable to provide food directly into a patient's jejunum without passing through the patient's stomach. This has typically been accomplished by using techniques similar to those described above, except that the internal end of a feeding tube is implanted in the patient's jejunum, instead of the patient's stomach. One difficulty, however, that has been encountered in implanting feeding tubes into the jejunum has been in the piercing of the jejunum by the access needle so as to create an insertion hole through which a guide wire or suture may be inserted. This difficulty arises, in part, because the jejunum is narrow and thus hard to locate externally and, in part, because the jejunum is not fixed within the body at any particular location. As a result, not only is it difficult to actually pierce the jejunum with an access needle (the access needle frequently missing the jejunum or just pushing the jejunum aside without penetrating it), but even if the jejunum is actually pierced by the access needle, subsequent movement of the jejunum may cause the access needle to become dislodged therefrom. Consequently, it is generally desirable to use as small a diameter needle as possible to pierce the jejunum. This maximizes the chance that the jejunum, if struck by the access needle, will be pierced thereby and also minimizes the size of the insertion hole (which is desirable for obvious reasons).
One approach that has recently been devised to address the above-identified problems with piercing the jejunum involves piercing the jejunum with a small diameter needle, grabbing the distal end of the needle with an endoscopically-placed snare, using said small diameter needle (with the snare secured thereto) to anchor the jejunum against the abdominal wall, piercing the thus-anchored jejunum with an access needle at a site proximate to the first piercing site, transferring the snare from the small diameter needle to the cannula of the access needle, removing the small diameter needle from the jejunum, and then proceeding in the conventional fashion by removing the needle of the access needle from its cannula, inserting a guide wire or suture into the cannula for grabbing by the snare, etc.
Another approach to piercing the jejunum is disclosed in presently-pending and commonly-assigned U.S. patent application Ser. No. 10/300,702, inventors Rebecca DeLegge et al., filed Nov. 20, 2002, and incorporated herein by reference.